The core principle established is that interacting Quantum Field Theories (QFT) cannot be solved exactly and must instead be treated via perturbation theory relative to a free field solution, parameterized by the coupling constant Lambda. This approach relies on decomposing correlation functions into spectral densities defined over physical states; specifically, rho(m^2), which encodes the probability of creating multi-particle or bound states versus single-particle poles characterized by the wavefunction renormalization constant Z. The theoretical significance lies in mapping how interactions modify vacuum-to-state amplitudes, determining particle stability and scattering probabilities while maintaining consistency with the parent discipline's framework of relativistic quantum mechanics.
The core principle established is that interacting Quantum Field Theories (QFT) cannot be solved exactly and must instead be treated via perturbation theory relative to a free field solution, paramet…